1. Field of the Invention
The present invention relates to a misfire detecting device of an internal combustion engine capable of detecting a misfire of an internal combustion engine utilized in an automobile or the like.
2. Discussion of Background
A misfire detecting device is disclosed in Japanese Unexamined Patent Publication No. 30932/1987. This device detects an inner cylinder pressure by an inner cylinder pressure sensor, at two points before and after a top dead center in compression of an engine which are apart from the top dead center by the same angular distance. When both pressures are almost equal, a judgment is made as a misfire of the engine.
However, the conventional device erroneously detects a misfire, when a pressure variation takes place due to a change of a combustion state, or when a noise is superposed on the inner cylinder pressure detection value.